The problem of automatically delivering laundry chemicals to washing machines in a commercial setting has long been dealt with by those in the industry. To be successful, such a laundry chemical dispenser must be economical, it must require a minimum of human interaction, and it must deliver, at different times, incompatible chemical agents.
Typically, three types of chemical agents are utilized in a wash cycle. These include a detergent, a sour/softener or souring agent, and a bleach. The detergent is alkaline, the sour/softener is acidic, and the bleach is a compound that contains chlorine. The detergent and the bleach are compatible chemicals. The sour/softener and the bleach are incompatible chemical agents. If the acidic sour/softener comes into contact with the bleach, toxic chlorine gas can form. Accordingly, care must be taken that the bleach and the sour/softener not be mixed together.
A great deal of work has been done in the past to design an automatic chemical agent dispensing system for use with multiple washing machines. An example of the designs emanating from such work is U.S. Pat. No. 3,160,317. The '317 is an electrically controlled, pneumatically operated system for servicing multiple washers. The '317 patent has multiple mechanical pumps for delivering a detergent and an alkali mix through independent plumbing to the washers. A key feature of the '317 patent is that it mixes a liquid silicate with a liquid caustic on site to make the alkali mix that is delivered to the washing machines.
A second design of a chemical dispenser utilized to dispense potentially incompatible chemicals is that contained in U.S. Pat. No. 4,691,850. The '850 patent has a single electric pump that draws liquid from a manifold. The manifold has multiple lines connected to various liquid chemicals. After dispensing a single chemical, a water flush cycle is initiated in order to flush the manifold and the pump to remove any traces of a chemical that may be incompatible with the succeeding chemical that is to be dispensed.
Another example of a chemical dispenser is that detailed in U.S. Pat. No. 4,845,965. The device of the '965 patent was designed to utilize a single common delivery system for each of the chemicals, even though such chemicals may be incompatible. In order to accomplish this, the '965 patent incorporates a rather complex flushing system that provides for a water flush of all common lines and sumps after the delivery of a specific chemical. The '317, '850, and '965 patents do not teach the use of common components for the delivery compatible chemical agents nor do they teach the use of pumps that deliver chemical agents by means of venturi action.
It would be beneficial to the industry to solve the aforementioned problems. A solution should include simple, reliable components. Additionally, the number of components should be minimized by incorporating commonality for the delivery of compatible chemicals.